[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-block] [PATCH 1/2] block: Open backing image in force share mode f
From: |
Fam Zheng |
Subject: |
[Qemu-block] [PATCH 1/2] block: Open backing image in force share mode for size probe |
Date: |
Fri, 15 Dec 2017 16:04:45 +0800 |
Management tools create overlays of running guests with qemu-img:
$ qemu-img create -b /image/in/use.qcow2 -f qcow2 /overlay/image.qcow2
but this doesn't work anymore due to image locking:
qemu-img: /overlay/image.qcow2: Failed to get shared "write" lock
Is another process using the image?
Could not open backing image to determine size.
Use the force share option to allow this use case again.
Cc: address@hidden
Signed-off-by: Fam Zheng <address@hidden>
---
block.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/block.c b/block.c
index 9a1a0d1e73..f236431da1 100644
--- a/block.c
+++ b/block.c
@@ -4593,10 +4593,11 @@ void bdrv_img_create(const char *filename, const char
*fmt,
back_flags = flags;
back_flags &= ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
+ backing_options = qdict_new();
if (backing_fmt) {
- backing_options = qdict_new();
qdict_put_str(backing_options, "driver", backing_fmt);
}
+ qdict_put_bool(backing_options, BDRV_OPT_FORCE_SHARE, true);
bs = bdrv_open(full_backing, NULL, backing_options, back_flags,
&local_err);
--
2.14.3